Adjustable field-rheostat.



P. J. RAY.

ADJUSTABLE FIELD RHEOSTAT. APPLICATION FILED SEPT. a, 1912.

Patented Aug. 19, 1913.

, a SHEETS-SEEET 1.

Witnesses I inventor 36km Attorneys.

P. J. RAY. ADJUSTABLE FIELD RHEOSTAT. APPLICATION FILED snrq. a, 1 12.

- Patented Aug. 19, 1913.

3 SHEETS-SHEET 2.

nventor,

Attorneys P. J, RAY. ADJUSTABLE FIELD RHEOSTAT. APPLIGATION IYILED snrr. s, 1912.

1,070,629, I Patented Aug. 19, 1913.

3 SHEETS-SHEET 3.

Witnesses Inventor,-

Attorneys 0 fklZJig; f

PAUL J. BAY, OF LAKEWOOD, OHIO.

ADJUSTABLE FIELD-RHEOSTAT.

1,070,629. Specification of Application filed September To all lI/L()II), it may concern:

lie it known that 1, PAUL J. RAY, a citizen of the United States, residing at Lakewood,

adjusted by inserting the resistance in series with the shunt field, this particular stiucture being designed to g ve infinitesimal speed changes, whereby the motor may have 1mparted thereto maximum speed.

' In view of the. fact that the torque of a direct current motor decreases as its speed is increased by the insertion of resistance in the shunt field, and as it is generally preferable to'sta-rt a direct current field controllcd motor at low speed, which speed gives maximum torque, it is desirable to use a field rheostat which automatically cuts out all resistance in series with the shunt field, when the line voltage is interrupted .whether because of disconnecting the motor from the line or other disturbances.

The primary object therefore of the present invention is the provision of an adjustable lield rheostat, which will attain ithe foregoing features and will permit of the actuation of the motor at any variance of speed from the minimum to the maximum.

With. the foregoing and other objects in view which will appear as the description proceeds. the invention resides in the combination and arrangement of parts and in the details of construction hereinafter described and claimed, it being understood that changes in the precise embodiment of the invention herein disclosed can be made within the scope of what is claimed without departing from the spirit of the invention.

In the drawings Figure 1 is a top plan view of the complete rheostat, with the dome or casing shown in section, an electrical diagram being connected to the rheostat toshow the insertion thereof in series with the shunt field of a motor. Fig. 2is a side ele vation of the mechanism, a section being taken through .the longitudinal central line of the cover, and the operating lever being i Letters P t n Patented Aug. 19,1 913.

3,1912. SeriaiNo. 718,428.

a similar view to Fig. 2 with the automatic means for releasing the lever. Fig. 4 is a diagrammatic view ofthe full electrical connection used with the form of rheostat as shown in Fig. 3. Fig. 5 is a plan view of a portion of the cover showing the scale and lever index to indicate the speed of the motor -controlled by the rheostat. v I I As the main features of the present rheostat are used in connection with the manually operated lever and also the automatijcally operated lever, thesdescription of the .same will be referred generally as applying 'to all views Referring to the drawings, the numeral 1 designates the base of the rheostat carrying the cover 2, which is provided with the elongated slot 2, said slot being positioned for the protrusion of the handle of the lever -3, the detailed construction and assemblage of which will be described la-ter'on.

Fixedly carried by the base 1, either integrally or otherwise, is a plate 4 which has secured thereto upon the inner face the two bushings or disks 5 made of'insulation, such insulation either being hard paper fiber or mica as may be desired, and although only two of the said disks are shown, it is evident that one or in fact any number may be used according to the desired amount of resistance needed, as will presently appear. 6011- meet-ed to the upper'ends of the i spective plates 4; by screws 7, and above each bushing 5, are the plates 6 also made of insulation the same extending in parallel and being connected by the slots 8 and screws 9 to the upper end of the adjustable plate 10, said plate 10 being constructed similarly to the plate 4 and at the opposite end ofthe based.

The foot or base 11 of the plate 10 is pro-' vided with the two slots' 12, through which project the bolts or screws 13, thus providing a means for adjustably connecting the plate 10 to the base 1. This construction permits of the easy assemblage of the parts of the rheostat as will presently appear.

Mounted in the respective plates 4 and 10 ,are the two cylindrical bolts or tie rods let, the heads 14 of which abut the plate 4, while the lock nuts 14? disposed upon the opposite ends thereof abutthe outer face of the plate 10. The particular ofiice of the respective bolts or tie rods will beset forthlater on. s v

Connected adjustahly to and carried by Waterl n -1Q.-ere-ribs:tmzcylin ri aliguide posed to the face of the plate 4: are the two disks or bushings 18 of lfiSLllZLtlO-ZL Dis posed upon the respective tie rods imlts a between the plates and -e bushing 01" sleeve 19 of 111SIllLt-1OD which with the disks 5 and 18 insulates the conductor disks 20 disposed upon the tube 19 of insulation and between the respective, pairs of disks 5 and 18. These disks 20 preferably made of graphite or carbon, and are disposed to compressed and released to decrease and increase the resistance placed in the shunt with the field of the mo tor. .As shown, two columns or" these disks 20 are provided and as the surfaces thereof when made of graphite or carbon, are comparat-ively rough, it is evidentthat when the compression is gradually released, the surface contact between the disks is therefore gradually broken'to adjustelbiy incifease the resistance of such'columns of; disas and in turn to increase the resistance inserted in series with the shunt field. of the moton The compression ofsaid disks will decrease the resistance so that the mimimuin speed required in the motor can be attained. Under normal conditions, the disks 20 are held compressed by the two springs 21, there being one spring to each column of disks, said springs being disposed upon the respective bolts or tie rods 14 between the plate 10 and bar 17, the force of the said springs being exerted away from the plate 10 and upon such bar 17.

In order to provide a means for adjustably increasing the resistance, that is re ducing the compression upon the respective columns of disks, the bar 17 upon the face abutting the respective disks 18 of insulation, is provided with the two apertured lugs.

22in which is mounted the pin 23, said pin. 23 having disposed. thereon between the lugs 22, an anti-frictional roller 24, said roller being disposed in the path to be engaged by the lower cam end 8 of the operating lever 3. 1 i

In o-i'derto properly mount the lever '3,

' two a pertured lugs 25 carrying the lever piv oting pin 9-6 are themselves carried by the plate 27'. In the under side of the base plate 1 are provided recesses and elongated slots 28, through which project the screws 29 for locking the plate 21in adjusted positicn.

In order to provide means for adjusting the late QTWhen'the screws 29 have been re- .eased, and thus regulate the position of the cam end of the lever 3 relatively to the accuses auti-frictionalroller 2 a screw threaded lug 30 is providedupon the inner end of the plate 2'1 and is engaged by the feed screw 31 which mounted in and at the base of the plate 1.0, the head thereof being disposed to be readily accessible for impart ing the necessary movement to the plate 27.

lvhere the handle is used to be held at any poinh to maintain the same in position, a fiat spring 33 is arried thereby, clearly shown in Fig. 2 and is posed to engage the adjacent face of the met 2 of the cover 2 and oii'crs suliicicnt resistance to maintain. the lever in any adjusted position in the Islet 2. 4

in the form of rheo'sta-t shown in Fig. 3, jtheelectromagnet 35 is mounted between the irespective disks 36 and 37 upon the handle :or lever 3 within the dome or cover 2, the jsame being so constructed and electrically connected, as will presently appear, to exert a magnetic pull upon the cover adjacent the slot 2 sufiicient to overcome the-tension oi? the spring 34, whose normal tension is to hold the lever in the position as shown in F 5;, thus providing a means whereby the lever 3 the slot'fE as long as the line voltage to the motor is not disturbed to any great extent. the coil 35 will be deenergized and thus release the lever 3 to the action of the spring 35% which will assume the low speed position as shown in Fig. 3. I

l vh'ere the rheostat is used without the electromagnet 35, the circuit is as follows; The current is led to the motor 50 through the mainsM-M', a conductor 5. being disposed relatively to the.motor 50 so as to form a shunt with the field thereof, said conductor 51 being" led to a post 52 carried by and insulated from the base 1 of the rheostat, the conductor 53 being connected to the first column of conducting disks 20, said It will thus be seen that when. the elements are in the position as shown in Fig. 1, that the rheostat will be in its lowest resistance position and that. the maximum currentwill be flowing, through the shunt field ot the motor- 5t), but should it bedesired to decrease the speed of the motor by increasingfthe rcsistancc the lever 3 s moved .u n'ardlyuso that the corn .3 thereof will abut the anti frictional rollepfl, thus m oving the bar Should the line Voltage be disturbed,

may be left in any position within- 17 against the tension of the springs 21 an permitting the separation of, the respective columns of disks 20, whose surfaces as before described being comparatively rough,

and also said disks being slightly separated will increase the resistance of the respective columns of disks, thus in turn increasing the resistance inserted in series with the shunt field of the motor. In this form, the spring 33 'ill maintain the lever 3 in any desired position relatively to the slot 2'. lt wiill thus be seen that by lowering or raising the lever 3, any speed may be obtained within the speed range of the motor.

As shown in Fig. 3, andin the diagram of Fig. 4, what is termed as a no voltage release attachment for bringing'the lever 3 to the low speed position, when the voltage is interrupted, is provided, and in this case, the elect-romagnet 35 is connected. across the main line terminals M-M' and the circuit is as follows: the main line terminal M, the conductor 51, the'post 52, the conductor 32, the binding post 39 mounted upon the near bar 6, the conductor 40, the conductor ll, the binding post L2 carried by the other bar (5, the conductor 43, the binding posttt connected to and insulated from the base 1, the conductor l5, and the main M. It will thus be seen that when the currentis flowing through the electromagnet 35, and under a slight variance, that the lever 3 will be maintained by the magnetic action oi the electromagnet- 35 upon the cover 2 adjacent-to the slot 2 and at any desired adjustment within the radius of such curve of the slot 2, but that should the line voltage be disturbed, the

coil 35 will be deenergized and thus release the lever to the action of the spring so that the lever 3 will be moved to the position as shown'in Fig. 3, releasing the bar 17 to the action of the springs-21, which thus compress the disks 20 and decrease the resistance thereof. Thus itwill be seen that when the lever 3 with the electromagnet 35 carried thereby is positioned at a place within the slot 2, the same will maintain such position as long as the line voltage to the motor is not disturbed to any great extent, whereas in the form shown in Fig. 1, where the spring plate 33 is provided, and no spring 3i is employed, the lever 3 will of necessity be maintained at any desired adjusted position relativelyto the slot 2, thus maintaining the spacing of the disks 20 in the respective columns in a fixed adjusted position. The lever 3 is provided with the index or pointer P, which points toward th'gage or scale Gr, to indicate the various motor speeds, so that the operator may set the le'ver 3 at any do; sired speed. I

The re stance coil R, by means of the coir ductor 2 1, is shunted across the terminals 52 and 55, and as this coil R, is of a higher resistance than the maximum resistance of From the foregoing description it is evi- 3 dent that with an adjustable field rhcostat,

constructed according to and embodying the present invention, the resistance disposed in series with the shunt field of the motorwill permit oI the starting of the motor at a low speed, the lever 3 at such time being moved the. full length of the slot 2 if necessary, and that when the motor has attained full speed, the lever will be adjusted to maintain the. same.

It will also be evident from the foregoin that the rheostat which is constructed according to the present invention, may have its columns of disk 20 increased or decreased in number according to the necessary amount of resistance and the length of the respective columns willalso be increased or decreased without departing from the spirit of the present invention.

\Ylmt is claimed is:

1. An adjustable field rheostat, having a l-asc, a pair of spaced supports carried by the base. two parallelly disposed rods connected to said supports, two series of conductor disks mounted one series upon each rod, both series combining to form a resistance medium, a plate slidably mounted upon both rods between one of the supports.

,basc, a pair of spaced supports carried by" the base, two parallelly disposed rods connected to said supports, two series of conductor disks mounted one series upon each rod, bath series combining to form a resistance medium, a plate slidably mounted upon both rods between one of the supports and the adjacent ends of the respective series of disks, two springs, one mounted upon each rod between the support and said plate for normally maintaining the series of disks compressed, a lever pivotally mounted upon the base between the rods, 2), pair of lugs carried by the plate adjacent the lever, anttfrictional means carried by said lugs and disposed in the path to be en'- gaged' by the lever to move the'sliding plate to compress the springs, and means for pressing position.

3. An adjustable field rheostat, having 'a base, a cover for the base having a handle receiving slot therethrough, a pair of spaced supports carried by the base, two paraileliy disposed rods connected to said supports,

[seen] Gerreciien-inimetters Patent No 1,07G,629i

emme through the siot of the cover, coacting means carried by the lever and sliding plate for compressing the springs to increase the resistance of the disks, and a spring plate carried by the lever for engagement with the adjacent portion of the cover "to maintain the lever in adjusted position. y

In testimony that I- claim the foregoing as my own, I have hereto aifixed my signature in the presence of Witnesses.

. PAUL J. RAY. Witnesses:

F. B. Annono, H. R. Gnow, E. D RAY.

It is hereby oertifiedithet in Letters PatentNo. 1,070,629; granted Augnist 19, 1913, rpon the application of Paul J. Ref, otLakewood,@hie, an improvement in Adjustable Field lthe ostetsj an error appears in the printed specification rennin ing correction as follows: Page 2, line 126, for the word deemerse read increase; and that the proper corrections hare heen made in the files and records of this ofiioe and are hereby made in said LettersPatent. i

Signed and seeded this 24th day February, A. 11, 1914;.

Acting Oommise'oner of Patents. 

